Oklahoma prison officials were spending Tuesday afternoon making final preparations for the state's first double-execution in nearly eight decades. Clayton Lockett is scheduled to die 6pm local time at the state penitentiary in McAlester; Charles Warner is scheduled to follow at 8pm. Both executions will be carried out with a drug cocktail in dosages never before tried in American executions.

Lockett, 38, was convicted in the killing of 19-year-old Stephanie Neiman in 1999. She was shot and buried alive. Lockett was convicted of raping her friend in the violent home invasion that lead to Neiman's death.

Warner, 46, was convicted of raping and killing 11-month-old Adrianna Waller in 1997. He lived with the child’s mother.

The state plans to lethally inject Lockett and Warner with midazolam followed by vecuronium bromide and potassium chloride. Florida has used a similar method, but it employed a dose of midazolam that is five times greater. And Ohio used midazolam with a different drug, hydromorphone, in the January execution of Dennis McGuire, which took longer than 20 minutes.

Oklahoma corrections spokesman Jerry Massie briefed the media and said the executions will likely take longer than normal, because the first drug is expected to work more slowly.“Don’t be surprised,” Massie said.

The inmates challenged the secrecy surrounding Oklahoma’s source of lethal injection drugs. They won at the state district court level, but two higher courts argued over which could grant a stay of execution. When the state supreme court stayed their executions so it could consider their constitutional claim, the Republican governor Mary Fallin said it had no authority to grant the stay. A House member said he would try to have the justices who wanted the stay impeached.

The court then ruled against the prisoners and lifted the stay.

Justice Steven Taylor wrote that Lockett and Warner were not entitled to know the source of the execution drugs. They "have no more right to the information they requested than if they were being executed in the electric chair, they would have no right to know whether OG&E or PSO were providing the electricity; if they were being hanged, they would have no right to know whether it be cotton or nylon rope; or if they were being executed by firing squad, they would have no right to know whether it be by Winchester or Remington ammunition,” he wrote.

Oklahoma representative Mike Christian said he would not withdraw the resolution to impeach the court justices.

“I realize this may sound harsh, but as a father and former lawman, I really don’t care if it’s by lethal injection, by the electric chair, firing squad, hanging, the guillotine, or being fed to the lions,” he said. “I look forward to justice being served.”

Former Oklahoma attorney general Drew Edmondson told The Guardian he predicts the representative’s impeachment resolution will “not see the light of day.”

“I would start off by saying I’ve been a supporter of the death penalty, but I firmly believe next to war it is the most serious thing a society can do and it needs to be taken very seriously,” he said.

“I’m certain that Representative Christian was telling the truth that it doesn’t matter to him, but it should matter to the rest of us.”

Lockett planned to have no last meal. He requested a steak dinner that was greater than the $15 limit, and said he wanted nothing when offered an alternative, said corrections department spokesman Jerry Massie. Warner plans to have a 20-piece order of boneless hot wings, potato wedges, fruit cups and coleslaw.

Massie said Lockett will be executed and then the media and any family of Lockett and his victims will be let out of the execution viewing area. Family will be allowed to give a statement and the process will repeat for Warner.

Massie told the media not to be surprised if an inmate says a comment similar to Oklahoma inmate Michael Lee Wilson's final statement in January. Wilson told observers "I feel my whole body burning" before he died.

The suggestion that inmates have intentionally made statements to bring scrutiny to executions came up in the prisoners' court case in March. The judge replied: “You think someone is dying and just makes that up?"

The office of the attorney general, Scott Pruitt, said the state has provided the prisoners’ attorneys with information about the drugs, excluding the source, as supported by the state law.

“Let’s be clear: throughout the legal wrangling, the attorneys for Lockett and Warner have not challenged whether they committed these atrocious crimes and are deserving of the maximum lawful punishment,” Pruitt said in a statement. “For more than 15 years, the state has worked diligently to see the will of the jury carried out and to ensure justice is served for Stephanie Neiman and Adrianna Waller. The administration of the death penalty is a solemn duty carried out by the state; and the courts have ruled the State of Oklahoma has done its job to ensure these executions proceed in accordance with the law.”

In a statement, Neiman’s parents asked the jury to sentence Lockett to death for killing their only child.

“She stood up for what was her right and for what she believed in,” they said. “And when Clayton asked her if she would tell, she said, yes she would tell. Right is right and wrong is wrong. Maybe that’s what Clayton was so scared of, because Stephanie did stand up for her rights. She did not back down to him. She did not blink an eye at him.”

Lockett’s prosecutor Mark L Gibson said in a letter Lockett deserved to be executed.

“In 28 years as a prosecutor, I never met or prosecuted anyone more filled with evil, and who thrived on being evil, than Clayton Lockett, including coming face-to-face with [Oklahoma City bomber] Tim McVeigh,” he wrote.

In addition to killing Neiman, Lockett “repeatedly threatened the lives of the victims, of jailers, and other law enforcement officers, which threats he enhanced by prolifically making weapons while incarcerated (with everything from toothbrushes to metal pieces he broke off in his cell) and promising escape,” Gibson added.

In Warner’s case, the victim’s mother asked for clemency. In a video at Warner’s pardon and parole board hearing, Adrianna’s mother Shonda Waller said she morally opposed the death penalty.

“That would dishonor my daughter,” she said. “It would dishonor me and everything I believe in. I wouldn’t want to have to know about something like that, because I wouldn’t want to know that my hand or what I went through personally is the reason why he is no longer living. When he dies I want it to be because it’s his time, not because he’s been executed because due to what happened to me and my child.”

Activists who oppose the death penalty planned a sit-in at Governor Mary Fallin’s office on Tuesday from 2pm until 5pm and a vigil outside her mansion at 5:15pm.

“Tonight, in a climate of secrecy and political posturing, Oklahoma intends to kill two death row prisoners using an experimental new drug protocol, including a paralytic, making it impossible to know whether the executions will comport with the Eighth Amendment’s ban on cruel and unusual suffering," said Madeline Cohen, a lawyer for Charles Warner.